Embodiments relate generally to marine geophysical surveying. More particularly, embodiments relate to incorporation of flexible printed circuits in marine geophysical streamers
Techniques for marine surveying include marine geophysical surveying, such as seismic surveying and electromagnetic (“EM”) surveying, in which geophysical data may be collected from below the Earth's surface. Geophysical surveying has applications in mineral and energy exploration and production to help identify locations of hydrocarbon-bearing formations. Marine geophysical surveying is typically performed using one or more marine geophysical streamers (or simply “streamers”) towed below or near the surface of a body of water. The streamers are typically cables that include a plurality of sensors disposed thereon at spaced apart locations along the length of the cable. The sensors may be configured to generate a signal that is related to a parameter being measured by the sensor. An energy source may also be towed through the water by the same or a different vessel. At selected times, the energy source may be actuated to generate, for example, seismic or EM energy that travels downwardly into the subsurface rock. Seismic or EM energy that interacts with interfaces, generally at the boundaries between layers of rock formations, may be returned toward the surface and detected by the sensors on the streamers. The detected energy may be used to infer certain properties of the subsurface rock, such as structure, mineral composition and fluid content, thereby providing information useful in the recovery of hydrocarbons.
In geophysical surveying, the streamer is typically a cable made of multiple components, such as a wire bundle and strength members, all bundled together and covered with a protective outer skin or “jacket.” The streamer may be up to several kilometers in length. A lead-in cable typically couples the streamer to the survey vessel. The wire bundle may be made up of electrical power conductors and electrical data communication wires. In some instances, fiber optics for data communication may be included in the wire bundle.
The wire bundles used in conventional streamers may have a number of drawbacks. For instance, the wire bundle may be susceptible to electrical interferences from adjacent wiring and can be co-located differently in each streamer section. This may create differences in electrical performance, which can cause anomalous electrical behaviors potentially resulting in non-reproducible failures. Current wire bundles also may consume a larger volume in the streamer requiring more buoyancy compensation and large sizes, which may limit the effective length of streamer a vessel can carry on a single winch. In addition, traditional wires may be insulated with various plastics which may be susceptible to mechanical deterioration and physical damage during the assembly process. Moreover, some current approaches that utilize individual wires and pairs of wires in the wire bundle may require time-consuming soldering to assemble with subsequent inspection to verify the soldering acceptability. Some current approaches may also utilize splicing of sensors and embedded electronics along the length of the streamer. This splicing process may be a time-consuming and costly part of the streamer assembly process. Additionally, this splicing process may have a relatively high failure rate during either assembly or use, for example, due to poor insulation of the splice or crossed wires.